Brought up in https://community.metabrainz.org/t/fr-variables-for-recording-relationships/814271.

For my specific usecase, I'd like the MBIDs of a recording's remixers, and the MBIDs of a remix's original recordings made available in variables to be used in a tagging script.

I'd like to be able to tag files with them such that linking between remixes (and remixers) is made possible in a "MusicBrainz-aware" music media server like LMS. For files tagged appropriately, it is already possible for tracks in an album to show Recording-Artist relations in its album view, and I would like to have this extended to show Recording-Recording relations, too.

Creating tags containing those values is fairly simple, but doing them manually for each recording (especially on a remix album) is tedious, thus I'd like to make a tagging script that writes the tags automatically.

While it would be nice if the tags were also created automatically (in-built in Picard), there's probably a lot of work and discussion to be had about tag names and mapping that, for a niche feature like this, probably doesn't need to happen.

I think info about the following relationships should be made available as variables:

• Artist-Recording
  • Remixer - Multi-value variable of MBIDs.
    Remixer is already a tag written by Picard, but I'd like the MBIDs of the remixers to be available.
  • Mix-DJ - Multi-value variable of MBIDs.
    Same as Remixer.
• Recording-Recording
  • Remix - Multi-value variable of MBIDs + (optional) multi-value variable of original recording names.
    Only the variable for the forward link relation (Remix of) should be made (Has remixes isn't particularly relevant).
  • DJ-mix, Samples material, Mashes up - Multi-value variable of MBIDs.
    Same as Remix.
  • Karaoke - Multi-value variable of MBIDs + (optional) multi-value variable of original recording names.
    This also only needs the forward link relation.
  • Instrumental, Edit - Multi-value variable of MBIDs + (optional) multi-value variable of original recording names.
    Same as Karaoke.

Edit: I think relationship attributes could be flattened for the purpose of tagging. I'm not sure I've ever seen an assistant remixer, and I don't believe what exactly a recording samples is too relevant.

The names of the original recordings would be nice to have, since it would allow a remix/mashup to show those names of the original recordings without them having to be present in the media library.

To be honest, I would love to write tags for every relationship possible. But I'll keep the scope small for now